Plate changer



March 24, 1942.

A. J. KIZAUR PLATE CHANGER 2 Sheets-Sheet 1 Filed May 25, 1940 QQ JF5 Male]! 24, 1942. 4J KIZAUR 2,277,330

PLATE CHANGER Filed May 25., 1940 2 Sheets-Sheet 2 15 fl g g Patented Mar. 24, 1942 UNITED STATES PATENT OFFICE 13 Claims.

My present invention relates in general to .apparatus for shifting sheets or plates of sensitive material in order to position the same successively for exposure in making pictures, and my invention has more particular reference to apparatus of the character mentioned for use in the production of radiographic or X-ray pictures of stereoscopic character.

Another important object is to provide apparatus for successively presenting a plurality of sheets or plates of material sensitive to X-rays or other rays in position for exposure; a further object being to provide plate changing apparatus of rugged and relatively simple construction, occupying a minimum amount of room.

Another important object is to provide apparatus for shifting the relatively heavy frames or cassettes in which sensitive material is preferably mounted for convenient handling and exposure; a further object being to provide apparatus for shifting relatively heavy cassettes smoothly and Without jar; a still further object being to provide apparatus of the character mentioned which does not require critical balancing or adjustment.

Another important object is to provide plate changing apparatus in which the weight of the cassettes is not a factor in the operation of the apparatus; a further object being to provide plate changing apparatus to perform its plate changing cycle whether or not cassettes are mounted therein.

Another important object is to provide plate changing apparatus in which the motion of the plate changing parts may be interrupted during the operating cycle of the device without danger of damage to the device or injury to the person of the operator, the apparatus being arranged to permit immediate stoppage of motion in the event that an arm, hand or other body member becomes positioned in the path of operating movementof the plate changing mechanism. 7

Another important object is to provide apparatus of the character mentioned which will perform its operating cycle instantly in response to pressure applied on a release button; a further object being to provide apparatus adapted to complete its operating cycle, whether or not the actuating button is held down throughout the operating cycle; a still further object being to provide for the prevention of a repeat cycle of the apparatus in the event that the button is held down after the completion of the plate changing operation.

Another important object is to utilize a motor driven reversible plate holder for plate changing purposes; a further object being to provide nonpositive driving means, preferably in the form of a friction clutch, between the motor and the reversible plate holder in order to allow the reversing movement of the plate holder to be interrupted without damage to the equipment at any stage in the reversing cycle of the appara- .tus.

Another important object is to provide for reversing the plate holder by a lever system in which there is no dead center position of the parts.

Another important object resides in the provision of simplified mechanism for reversing a plate holder in which the plate holder is pivoted for turning movement on a slide which, in turn, is mountedin a way extending parallel with respect to the plane of the reversible holder, and including lever means actuated from a suitable power source for drawing portions of theholder remote from its pivoted axis on the slide in a lateral direction with respect to said way in order to obtain the reversal of the plate carrier in place.

These and numerous other important objects, advantages, and inherent functions of the invention will be fully understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the invention.

Referring to the drawings:

Figure 1 is a perspective view of apparatus embodying my present invention;

Figures 2 and 3 are sectional views taken sub stantially along the line 2-2 in Figure 1, showing the apparatus in two positions during'the plate changing movement;

Figure 4 is a sectional view taken substantially along the line 4-4 in Figure 2;

Figure 5 is a sectional view taken substantially along the line 55 in Figure 4;

Figure 6 is an enlarged sectional view taken substantially along the line 66 in Figure 5; and

Figure 7 is a diagram of electrical connections.

To illustrate my invention, I have shown on the drawings plate changing apparatus II, comprising suitable frame means forming the opposite side walls l3, the back wall I5, a top wall l1, and a bottom wall I9 of a casing 2 l. The casing 2! may conveniently be formed of sheet metal, but, of course, any other suitable material may be utilized to formthe casing in which is disposed the operating parts of the plate changing equipment. Where used in making X-ray pictures, the casing may, if desired, be formed of material impervious to X-rays, or may be lined with such material, although such refinement is by no means essential, nor is the invention necessarily restricted to a casing, the casing being preferred for the purpose of housing the plate changing equipment and affording an attractive appearance.

The front of the casing is provided with an opening 23 which, in the illustrated embodiment, is closed by means of a curved panel 25 of X-ray transparent material, which is secured in the opening in any suitable or preferred fashion as by means of a finishing strip 21 held, as by suitable fastening means such as screws, upon the edges of the panel and on the edges of the casing which define the opening 23.

Side walls |3 are provided with elongated slotlike openings 29 adjacent the forward edges of said side walls, and means forming a way 3| is secured within and on the bottom wall of the casing 2| in position extending between the opposite side walls l3 at the lower ends of the openings 29, a similar way being secured to the upper wall H in position extending between the upper ends of the openings 29, whereby said ways are facing and parallel within the casing 2|.

The plate changing mechanism within the easing 2| comprises a carrier 33 formed with pivot means 35 defining an axis adjacent one end of the frame about which axis the frame is turnable, said pivot means, at the lower edge of the frame, including a slide pin portion 3'! which extends in the way 3| and including, at the upper edge of the frame, a similar slide pin portion extending in the upper way.

The carrier 33 comprises a panel embodying a plate 39 of material, such as lead, impervious to X-rays, which is held by and between a pair of supporting layers 4|, the edges of the plates 39 and 4| being secured together by edge pieces 43 defining the edges of the carrier. The opposed faces of the carrier carry plate supporting means 45 at or adjacent and preferably parallel with respect to the opposed upper and lower edges of the carrier. In the illustrated embodiment, the plate supporting means 45 comprise channel members forming facing grooves on the opposed faces of the carrier in which grooves the upper and lower edges of a plate or film enclosing cassette 4'! may be received, whereby a pair of cassettes 41 may be mounted on the opposed faces of the carrier, the cassettes, when mounted, facing outwardly of the carrier in opposite directions.

It will be seen that the cassettes 4'! may be easily mounted on the carrier 33 by inserting the same through the openings 29 when the carrier is in position between and parallel with respect to the guide means 3|. It will be seen also that when the carrier is in cassette receiving position with the pivot means 35 at one end of the guideways, one of the cassettes will be .in exposable position in the opening 23. By tilting the carriage about the pivot means 35 while moving the same along the guideway to the opposite end thereof, the position of the carriage will be reversed, thus presenting the other cassette in exposable position in the opening 23.

In making an exposure, the patient or other object to be pictured is placed in front of the curved panel 25, said panel being curved, more particularly, to facilitate the placement of the chest portions of the patient closely adjacent the cassette which, when in exposable position on the carrier 33, is disposed immediately behind the panel 25. Obviously, the panel 25 could be omitted but is preferred in order to aid the patient in maintaining unchanged position with respect to the apparatus without interfering with the plate changing movement of the carriage. This is accomplished by pressing the patient upon the panel 25, and the patient may, if necessary, be strapped in place.

The exposure, of course, may be made in accordance with usual radiographic technique by placing a source of Xrays at a predetermined distance directly in front of and in line with the opening 23, so that X-rays from the source may penetrate the patient and impinge upon the sensitive material in the cassette 41, which is in position facing the opening. Thereupon, the carriage 33 may be reversed to present the other cassette in exposable position while the position of the patient is maintained unchanged; and thereupon the second exposure may be made.

In making stereoscopic X-ray pictures, the position of the light source is slightly changed by shifting the same so that in successive exposures, X-rays from the source impinge on the sensitive material at unlike angles. It is apparent, how ever, that immobility of the patient is essential to the production of successful stereoscopic pictures, and I have therefore provided plate changing equipment for reversing the position of the carriage 33 substantially without jar or vibration.

To this end, the frame forming the casing 2| is of rugged construction, and provision is made for supporting the casing firmly in place. An important feature of the present invention resides in the provision of mechanism for accomplishing the reversal of the carriage 33 with utmost smoothness.

The carriage reversing mechanism comprises an arm 5| pivoted, as at 53, on one side of the casing 2|, the arm 5| being preferably fastened on a vertical shaft 55 suitably journaled at or adjacent its opposed ends in suitable spaced bearing means 51 rigidly mounted on the casing 2|. The end of the arm 5| remote from the pivot 53 is turnably connected on the carrier 33 intermediate the opposed sides of the carriage, the connection preferably comprising axle means 59 in the form of a pin on the carriage preferably at the lower edge thereof, said pin being journaled in the arm 5|. If desired, the axle means 59 may comprise another pin at the upper edge of the carriage and received in an arm similar to the arm 5| and fastened on the shaft 55.

Figure 2 of the drawings shows the carriage in position presenting one of the cassettes in exposable position in the opening 23. After such cassette has been exposed, the other may be presented in position to be exposed in the opening 23. By rocking the arm 5| in a clockwise direction, viewing Figure 2, the medial portions of the carriage will swing about the pivot 35 in a counterclockwise direction, and the pivot means 35 will be simultaneously drawn toward the right, viewing Figure 2, thereby imparting a turning movement to the carriage 33. When the pivot means 35 reaches the right-hand end of the guideway 3|, the carriage will have turned about completely to present the cassette, containing unexposed film, in position to be exposed in the opening 23. It will be seen, however, that during substantially the first half of the turning movement, the arm 5| will move in a clockwise direction but will return in a counter-clockwise direction during substantially the terminal half of thecarriage turning movement.

In order .to rock the arm I provide a crank 6I drivingly connected with motor means 85, and a connecting rod 63 pivotally secured at its oppositeends, respectively, on the crank 6| and on the arm 5I intermediate the pivot means 53 and 59. By rotating the crank through one complete turn from the position shown in Figure 2, the arm -5I first will be rocked in a clockwise direction until the position shown in Figure 3 is reached, after which the continued movement of the crank will cause the arm 5I to be returned in a counter-clockwise direction. It will be noted that utilization of the crank 6I in this fashion imparts substantially simple harmonic motion to the arm 5I. Carriage turning movement thus starts slowly, the carriage attaining maximum turning speed when the parts are in position shown in Figure 3, and thereafter being decelerated with the motor connected crank 6| operating, in effect, as a brake to bring the carriage to a stop gently at the conclusion of its turning movement. Since the carriage has appreciable weight, its momentum, when traveling at maximum speed in the position shown in Figure 3, will always carry the carriage past the only dead center position afforded by the mechanism.

After completion of the carriage reversing cycle, it is not necessary to reset the mechanism to a starting position, but after the operating cycle of the mechanism has been completed, with the exposure of the film on both sides of the carriage, the film containing cassettes may be dismounted from the carriage through the openings 29, and cassettes containing unexposed film may then be mounted on the carriage without resetting the same, since the reversing mechanism is operable to reverse the carriage, starting from the position shown in Figure 2, with the slide pivot 35 at the left-hand end of the track 3|, or from the reverse position in which the slide roller is at the righthand end of the track,

The bottom I9 of the casing 2I forms a mounting for a housing II containing reduction gearing comprising a worm wheel 13, and a worm I5. The worm wheel is drivingly connected on a shaft 'I'I which projects through the wall I9 and to the end of which the crank 6| is drivingly connected. The opposite end of the shaft TI projects from the housing II and carries a control disk 19. Preferably the wheel 13 is drivingly connected with the shaft T1 in non-positive fashion, permitting the-shaft 11 to turn with respect to the wheel in the event that the wheel movement be blocked for any reason, as by the entanglement of a body member of the patient or operator with the eassette carriage 33 during the reversing movement of the carriage. To this end, the wheel I3 is loose on the shaft 11, being clam'pingly secured thereon by and between friction plates 69 splined or otherwise drivingly connected with the shaft. Means is provided for pressing these plates 69 together on the shaft and into frictional engagement with the opposite sides of the wheel I3 in any suitable fashion, as by means of an abutment 68 and spring means 61 on the shaft and operating to press the plates 69 together on the wheel I3.

The worm I5 is housed in a cylindrical extension III of the housing II and is formed or otherwise fastened on shaft means projecting at the opposite ends of the extension 8|, whereby the worm I5 may be coupled, as at 83, with motive means .95, preferably. an electric motor supported on the underside of the casing wall I9 which is preferably formed with an offset inverted pan portion 61. The worm I5 may also be connected with brake means 89 comprising a split collar 9| suitably supported on the wall I9 andencircling an extension of the worm shaft, said split collar being provided with spring means 93 normally closing the collar upon the worm shaft, means being provided for releasing the brake against the braking urge of the spring 93.

The control disk I9 is generally circular, as shown in Figure '7, but has a flattened edge 95 on one side which edge, when the equipment is in normal or standby condition, faces switch means 91 comprising a pair of normally open switches 98 and 99. These switches comprise spring arms IOI, I93 and I05 mounted in a suitable insulating block I01, the arms IIlI and I03 forming the switch 98 and the arms I93 and I05 forming the switch 99. The control disk 19, being drivingly connected through the worm wheel and worm with the motor 85, will turn with the shaft 11 during the operating carriage reversing cycle of the apparatus. When the flattened edge 95 of the disk is in position facing the switch means 91, the switches 98 and 99 are open but will close as soon as the disk is turned from the standby position shown in Figure '7, and will remain closed until the disk again reaches standby position after having turned through a complete revolution, whereupon the switches will open.

Means is provided for energizing the motor from a suitable power source I09 under the control of'a push button switch III. To this end, a power conductor I I3 from one side of the source to one side of the motor 85 is provided. Another conductor II5 adapted for connection with the other side of the power source extends to one side of the push button switch III. The other side of the switch may be connected, as by the conductor III, to the blade of a double pole switch II9. This switch preferably is normally biased, as by the spring I2 I, to make connection with the motor 85 through a conductor I23. By closing the push button switch III, power may thus be delivered to the motor through the switch II9. As soon as the motor starts in operation, it will turn the shaft 11 and start the carriage reversing movement by turning the crank 6|. At the same time, the control disk 19 will be turned, thus causing closure of the switches 98 and 99. Upon the closure of the switch 98, the push button and the switch II9 will be short circuited, thus connecting the conductor H5 directly through the switch 99 to the conductor I23, thereby insuring operation of the motor until the switch 98 opens at the conclusion of the operating cycle when the flat edge of the disk reaches the standby position shown in Figure '7. Upon the closure of the switch 99, a circuit is completed from the conductor II3 through a relay coil I25 and through the switch 99 and a conductor I21 to the conductor H5, whereby to energize the relay coil and keep the same energized until the switch 99 is opened at the conclusion of the operating cycle of the apparatus. The relay coil I25 is operatively associated with the switch I I9 to open the same upon the closure of the switch 99 and thus cut out the push button III from controlling connection with the motor 85 during the operating cycle of the equipment, thereby obviating the necessity of holding the button switch down during the operating-cycle.

It will be noted that when the switch H9 is in shifted position under the influence of the relay coil I25, it completes a circuit from the conductor II5, through the button switch III, the condoctor I I1, and the relay coil I25, to the conductor I I3, so that if the button switch is held closed throughout the operating cycle of the apparatus and after the conclusion thereof, the coil I25 will continue to be energized and to hold the switch H9 in position to disconnect the button switch from the motor, thereby preventing a spurious repetition of the operating cycle; but in order to obtain a repetition of the operating cycle, it is necessary to release and repress the button after the conclusion of a preceding cycle.

Where braking means 89 is used, a brake releasing relay coil I29 may be connected between the conductors H3 and I23 as shown, whereby the brake 89 may be released against the urge of the spring 93 as soon as the motor 85 is energized, the brake releasing force being discontinued and the brake being allowed to close under the influence of the spring 93 as soon as the motor 85 is stopped by the opening of the switch 98 at the conclusion of the operating cycle of the apparatus.

Suitable means is provided for supporting the plate changing mechanism II at a suitable elevation and, to this end, I preferably provide mounting means permitting the elevation of the equipment II to be adjusted. As shown on the drawings, the mounting preferably comprises a support frame I 3I comprising a pair of spaced uprights I33 on and between which the casing 2| is supported for adjustable vertical movement. The uprights I33 may conveniently be formed as sheet metal channels which are interconnected, braced and held in spaced relationship by means of a plate or panel I35 and by means of a cap I31 interconnecting the upper ends of the uprights I33 and a brace member I39 interconnecting the lower portions of the uprights. If desired, the support frame I3I may be fastened or anchored directly on a building wall, or it may be mounted on a suitable support pedestal or stand I4I so that the apparatus may be selfsupporting in vertical position in any location in which it is desired to use the same.

The uprights I 33 form track means comprising guide rails I 34. with rollers I36 for supporting the same movably on the rail means and carries a shaft I43 journaled in the casing 2| with the opposed ends of the shaft extending into the channel members I33 and carrying rollers I44. Each of the wheels I44 co-operates with a wheel I36 on the opposite sides of a sheet metal strip forming the rail means I 34 so that the wheels I44 have tight frictional contact with the rail means I34 to form frictional driving connection therewith. Obviously, the member I44 and the rail portions with which it co-operates may be formed, respectively, as pinion and rack means, although I find it simpler to make the parts as rollers frictionally engaging the rail in order adequately to support the mechanism in adjusted position and to move the same on the uprights I33.

The shaft I43 preferably extends in a housing I45 fastened on the bottom wall I9 of the casing 2|, said housing forming an enclosure for the shaft I43 and driving mechanism I41 which is drivingly connected with the shaft I43 and also the housing I45 enclosing the gear box H, the motor 85 and the brake means 89.

The driving mechanism I41 for adjusting the The casing 2I is provided elevation of the plate changing apparatus comprises a gear I49 drivingly connected with the shaft I43 within the housing I and a pinion I5I drlvingly connected with the gear I49 and fastened on a shaft I53 which is journaled in the housing I45. The shaft I53 carries a sprocket I55 which is drivingly connected, as by means of a chain I51, with a sprocket I59 on a stub shaft I6I which is journaled in an end wall of the housing I45 and has an end extending outwardly thereof and carrying a crank I63. In order to secure the mechanism in adjusted position, the shaft I53 carries a ratchet wheel I with which is associated a holding pawl I61, said pawl being pivoted on a bracket I69, which is fastened on the bottom wall I9 of the casing 2I and which forms support for bearings in which the shaft I43 and an end of the crank shaft I63 are journaled. The pawl I6! is normally spring-pressed toward operative engagement with the ratchet wheel I65, which is preferably frictionally held on the shaft I53 so that the mechanism is supported in adjusted position on the uprights I33 by the latching pawl I61 through the frictional grip of the wheel I65 on the shaft I53, the ratio between the gears I49 and NH being such that this frictional grip is able to support the relatively large weight of the mechanism. Turning of the handle I53, however, in a direction to lower the casing 2| on the uprights I33 will cause slippage of the friction clutch means between the wheel I65 and the shaft I53, thus permitting the housing and its enclosed mechanism to be lowered to any desired position. In raising the housing, the wheel I65, of course, will turn with the shaft I53, the pawl I61 simply slipping over the teeth of the ratchet wheel I65.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction, and arrangement of the several parts without departing from the spirit and scope of the invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. A plate shifter for X-ray sensitive material comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, and driving means connected with said panel means and operable to reverse said panel means in place, whereby to successively present light-sensitive material 011 the opposite sides of said panel means in position for exposure.

2. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, including track means forming a track, follower means on the panel means for conmeeting the same at one end for sliding movement along and relative angular movement with respect to said track means, and means connecting said driving means on said panel means in spaced relationship with respect to said follower means.

3. A. plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, including means for mounting the panel means for pivotal and sliding movement about an eccentric axis in a predetermined path, said driving means being connected to exert pressure on the panel means in a direction laterally with respect to said path of movement, whereby to turn the panel means about said axis and move the same in said path in order to reverse the panel means in place.

4. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein the driving means is pivotally connected on the panel means at the medial portions thereof, whereby to draw the central portions in a direction laterally with respect to the said path along which the guided portions of the panel means are moved.

5. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein said driving means comprises a rotatable crank connected with the panel means to impart simple harmonic motion thereto in turning the same so that the panel means may be uniformly accelerated from and deoelerated to stationary position to thus accomplish reversal of the panel means without jar.

6. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein the driving means comprises motor means drivingly connected with the panel means through a slip clutch to prevent damage to the panel means if obstructed during its cycle of reversing movement.

'7. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein the driving means comprises a crank, means for turning the crank, and a connecting rod drivingly interconnecting the crank with said panel means.

8. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein the driving means comprises a shaft, means to turn the shaft, means drivingly connecting the shaft with said panel means, brake means normally holding the shaft in brake condition, and means for releasing said brake during the cycle of reversing movement of said panel means.

9. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein said driving means comprises an electric motor drivingly connected with said panel means, and switch means for controlling said motor, said switch means being controlled by said panel means.

10. A plate shifter for X-ray sensitive material, comprising panel means, means for support ing sensitive material on the opposite sides of said panel means, driving means connectedwith said panel means and operable to reverse said panel means in place, wherein said driving means comprises an electric motor drivingly connected with said panel means, switch means for controlling saidmotor, manually operable means for starting said motor in operation, and control means controlled by the position of said panel for maintaining said motor in operation during the course of the reversing cycle of ,said panel means and operable to stop the motor at the conclusion of the reversing cycle.

11. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein said driving means comprises an electric motor drivingly connected with said panel means, switch means for controlling said motor, manually operable means for starting said motor in operation, and control means controlled by the position of said panel for maintaining said motor in operation during the course of the reversing cycle of said panel means and operable to stop the motor at the conclusion of the reversing cycle, said control means comprising a control member drivingly connected for movement with said panel means and operatively associated with said switch means to maintain the motor in operation during the reversing cycle of said panel means and to disable the motor at the conclusion of said cycle.

12. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein said driving means compries an electric motor drivingly connected with said panel means, switch means for controlling said motor, manually operable means for starting said motor in operation, control means controlled by the position of said panel for maintaining said motor in operation during the course of the reversing cycle of said panel means and operable to stop the motor at the conclusion of the reversing cycle, said control means comprising a control member drivingly connected for movement with said panel means and operatively associated with said switch means to maintain the motor in operation during the reversing cycle of said panel means and to disable the motor at the conclusion of said cycle, separate manually operable switch means for starting the motor in operation, and interlock means associated with said separate switch means for preventing operation of the motor after the conclusion of an operating cycle until after said separate switch means has been manually released.

13. A plate shifter for X-ray sensitive material, comprising panel means, means for supporting sensitive material on the opposite sides of said panel means, driving means connected with said panel means and operable to reverse said panel means in place, wherein said driving means comprises an electric motor drivingly connected with said panel means, switch means for controlling said motor, manually operable means for starting said motor in operation, control means controlled by the position of said panel for maintaining said motor in operation during the course of the reversing cycle of said panel means and operable to stop the motor at the conclusion of the reversing cycle, said control means comprising been manually released, said interlock means comprising a holding relay adapted to disable motor control by said manual switch, and means, operable upon the commencement of the reversing cycle, to energize said relay and to deenergize the same at the conclusion of the operating cycle only in the event that said manual switch shall have been released at the conclusion of said operating cycle.

ARTHUR J. KIZAUR. 

